Means for corrugating tubing



Feb. 13, 1934. Y H H BABCOCK 1,946,472

MEANS FOR CORRUGATING TUBING Filed July 30, 1932 4 Sheets-Sheet 1 f/ J2L! o N513// wW/W/'mz may* l Feb. 13, 1934. H. H. BABcocK MEANS FORCORRUGATING TUBING.

Filed July 30, 1952 4 Sheets-Sheet 2 H. H. BABcocK 1,946,472

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H. H. BABCOCK MEANS FOR CORRUGATING TUBING Feb. 13, 1934.

Filed July 30, 1932 -4 Sheets-Sheet 4 Patented Feb. 13, 1934 MEANS FORCORRUGATING TUBING Henry H. Babcock, Oak Park, lll., assigner to TheBishop & Babcock Manufacturing Company, Cleveland, Ohio, a corporationof Ohio Application July 30, 1932. Serial No. 626,356

Claims.

This invention relates to corrugated metal tubing, and has to do withmeans for subjecting tubular metal blanks to axial and radial pressureand thereby contracting the blank axially and 5 extending it radially soas to form corrugations therein.

It is known to produce metal bellows or corrugated tubes by subjecting atubular metal blank to internal pressure and expanding it radially l0between spaced and relatively movable dies, while subjecting the blankto endwise pressure so as to contract it axially and move the diestogether for shaping the corrugations. Such a method and apparatus forperforming the same are disclosed in the patent to Hollerith andMetcalf, No. 349,718, dated September 28, 1886. Various modifications ofthe method and apparatus of the Hollerith and Metcalf patent have beenproposed.

Metal bellows or corrugated tubes of the character referred to areextensively used for the construction of thermostats and various otherdevices in which the bellows is alternately expanded and contractedaxially. It is important in a bellows of this type that the corrugationsbe truly radial to the bellows structure and be free from anyirregularities such as would interfere with proper flexing of thecorrugations.

In the production of a bellows in the manner` referred to, the volume ofthe tubular blank varies materially during the corrugating operation.For example, a cylindrical tubular blank 3 3/64ths inches long and withan interior diameter of .957 inches and an outside diameter of .969inches has a volume of 35.3 cc., and this same blank, when formed into abellows having four corrugations each of 1.428 inches outside diameter,and

a length of l--nds inches, has a volume of but 22.9 cc. When the blankis rst subjected to internal and axial pressure, the volume thereof .10increases from 35.3 cc. to 39.4 cc., and as the corrugating operationproceeds, the volume of the blank decreases to 37.7 cc., then increasesto 38.5 cc. an'd thereafter decreases to 34.8 cc., 31.4

cc., and, when the bellows is completed the volume thereof is 22.9 cc.as above noted. The variation in volume of the blank during thecorrugating operation is due to the change in form of the blank and notto stretching of the metal thereof, since, in the instance above noted,the metal of the blank is displaced and redistributed but is notstretched to any appreciable extent, if at all. It will be seen, fromthe instance above referred to, that the volume of the blank beingcorrugated rst increases, then decreases, and again increases, andthereafter decreases, during the corrugating operation. If the blank issubjected to endwise pressure of considerable value,

at the instant that the volume of the blankincreases, this endwisepressure is apt to cause buckling of the wall of the blank withresulting 60 distortion of the vcorrugations being formed and theproduction of body wrinkles, since the increase in volume of the blankresults in the wall of the blank being completely relieved of internalpressure during the interval required to 65 fill, by liquid, the spaceprovided by the increased volume of the blank. It is duringthis'interval required to fill the increased volume of the blank, eventhough short, that the damage is done by the endwise pressure to whichthe blank is subjected. On the other hand, when the volume of the blankdecreases, if the endwise pressure is unrelieved the blank is apt to bestretched to an objectionable extent in order to accommodate the body ofliquid retained therein. In all methods and apparatuses for producingmetallic bellows by subjecting a tubular metal blank to endwise andradial pressure, with which I am familiar, the endwise pressure and theinternal pressure are sustained throughout the operation and noadequate' provision is made for compensating for the above referred tovariations in volume of the blank being corrugated. As a result, inmetal bellows produced in accordance with present practice, thecorrugations of the bellows are frequently more or less undulatoryratherl than being truly radial to the bellows, and present portionswhich resist expansion and contraction of the bellows to an undesirableextent, such portions being relatively rigid and causing crack- 9o ingof the bellows contiguous thereto. Also, in many instances thecorrugations of the bellows are apt to contain wrinkles which materiallyinterfere with proper extension and compression thereof, and are apt tobev thinner than the wall of the original tube due to the stretchingaction above referred to. In producing metal bellows in accordance withpresent practice, in which the variations in volumev of the blank duringthe corrugating operation are not compensated for, it is extremelydiicult and, from a practical standpoint, impossible to produceuniformly perfect bellows.

My inventionis directed primarily to means for producing metal bellowsfrom tubular metal blanks in such manner as to compensate for variationsin volume of the blank during the corrugating operation, thusV avoidingthe objectionsabove noted to the present practice and assuring theproduction of uniformly perfect bellows in which the corrugations arefree from wrinkles or distortions such as would interfere with freeexpansion and contraction thereof. A further object is to provide meansfor producing metal bellows by displacing and flowing the metal of thetubular blank, rather than stretching the blank radially, so that thewalls of the corrugations of the finished bellows are of the samethickness as that of the original blank or, at any rate, are notstretched or thinned to an objectionable extent. A further object is toprovide a means of the character stated particularly adapted forcorrugating tubular blanks'of considerable length. In general, theobject of the present invention is to provide an improved apparatus ofthe character referred to, to the end of speed and uniformity forcommercial purposes. Further objects and advantages of my invention willappear `from the detail description.

In the drawings:-

Figure 1 is a plan view of invention; 1,

Figure 2 is a section `taken substantially on line 2 2 of Figure 1,partsbeingshown in elevation;

Figure 3 is a sectiontaken;substantially on line 3 3 of Figure 2, with`partsbrok'en away and in section;

Figure 4 is a section taken substantially online 4 4 of Figure 2, theend die'. ringand the yblank being shown fragmentarily .andyinl/section;

Figure 5 is` a section ytaken!substantally on line 5 5 of Figure 4, onanenlarged scale, the end die ring and associated parts being shownfragmentarily;

Figure 6 is a section taken substantially on line 6 6 of Figure 2;

Figure '7 is a view similar vto Figure 2, with the drive gear andassociated parts omitted, after initiation of the corrugating opertion;

Figure 8 is a view similar to Figure '7 after completion of thecorrugating operation;

Figure 9 is a view similar to Figure 1 illustrating a modied form ofapparatus;

Figure 10 is a fragmentary plan View, on an enlarged scale, of one ofthe` guide bars and associated parts, partly broken away and in section.

I provide a machine for subjecting the tubular blank to radial and axialpressure While compensating for variations in the volume of the blankduring the corrugating operation. This machine includes a base frame 1comprising side bars 2 which connect a xed head 3 at one end of theframe and a bracket 4 at the other end of the frame. An upright 5, rigidwith the base frame, is disposed intermediate head 3 and bracket 4. Thisupright slidably receives a tubular neck 6 of a movable head '7, thishead and head 3being disposed in spaced relation for receptiontherebetween of a tubular metal blank 8 to be corrugated.

The ends of blank 8 abut the inner faces of heads 3 and 7 and may besecured thereto, in any suitable manner, to effect a fluid tight andpressure resistant closure therewith. In the form of spaced relationalong the blank 8 andmountedv for relative movement toward'eachother,ARethe ar'JparatusE-of1 my y ferring more particularlyto Figure 3, eachring 29 comprises two sections 12a and 13a of semicircular shape, thesesections being hinged together at 14. Section 12a is provided, at thefree end thereof, with an outwardly projecting lug 15 tol which twolinks 16 are pivotally secured at 17, these links being disposed atopposite sides of the lug. A cam`lever 18 is pivotally mounted at 19between the links 16 at the other end thereof. When the ring 29 isclosed, a lug 20 projecting from the free end of section 13a extendsbetween the links 16 and cooperates with the cam lever 18, when thelatter is swung downwardly into operative position, for locking thesections of the ring tightly together.

Rings 9 are constructed similarly to rings 29, in general, and eachcomprises two sections 12 and 13 lpivoted together and secured closed bycam means lsimilar to the securing means of Fig. 3. Themeans forsecuring rings 9 to the heads 3 and '7 is thesame in each instance, anda description of the securing means for one of the rings 9 will suffice,Each section of ring 9 is provided with two studs 21 which project fromthe outer face of the ring, each of these studs having a head 22, theinner face of whichis shaped to provide a camming surface. Head '7 isprovided, at the inner face thereof, with openings 23 suitably.

shaped and of proper size and spacing to accommodate the heads of studs2l, and with arcuate slots 24 extending from the openings or recesses23. The slots 24 are of a Width to accommodate the Shanks of the studsso that the side portions of the stud head engage behind shoulders 25 ateach side of slot 24 and projecting from the side walls of groove 26which receives the head of the stud. The outer surfaces of shoulders 25are inclined outwardly and away from recess 23 and provide cammingsurfaces which cooperate with similarly inclined surfaces on the heads22 of studs 2l. By inserting the studs 21 into recesses 23 and thenturning the ring 9 in a clockwise direction, as Viewed in Figure 4, thering is secured to head 7 and is forced toward this head so as to clampflange 10 tightly between the ring and gasket 1l. Conveniently, eachsection of the ring may be provided, at the periphery thereof, with anopening 27 for reception of a pin of a Spanner wrench or otherappropriate tool for turning the ring in the manner described. Thisprovides convenient means for quickly releasing or securing the ends ofthe blank to the head with facility and expedition.

Each of the rings 9 is provided in its inner face with an annular recess28 corresponding in size and shape to one-half of the desiredcorrugation. Each of the rings 29 is provided, at each side thereof,with a recess 30 similar to the recesses 28 of the rings 9.

Section 12a of each of the rings 29 is provided 'c by pins 33, inslotted lugs 34 projecting laterally x from head 3 and upright 5. Asimilar guide bar 35 is secured at its ends, by means of pins 33, inslotted lugs 34 extending from the other side of-head 3 and upright 5.This bar nts into slotted lugs 36 extendingfrom sections 13a of rings29,

these lugs 36 being open 'at theirouter sides.

Head 'Imay beprovided' with lugs 'la and 7b,l

as in Fig. 1, which lugs accommodate and cooperate with the guide bars32, and 35, these lugs being similar to lugsI 31' and36, respectively,of

n having driving connection, through rings 29. Bar 35 is suitablyrounded at one end so that by removing the pin 33 at the other endthereof this bar may be swung outwardly into inoperative position so asto clear lugs 36 of sections 13a of rings 29 and permit sections 13a ofthese rings to be swung downwardly, when the cam locks are released,into inoperative position for removal of the corrugated blank orinsertion of a blank to be corrugated. A guide rod 37 is suitablysecured at one end to head 7 and is slidable through head 3 which isprovided, for this purpose, with an opening snugly receiving the rod.`Rod 37 is disposed adjacent the lower end of sections 12a of rings 29,and section 12a of each of these rings isl provided with an arcuaterecess which receives the rod. When sections 13a of the rings 29 areopened, rod` 37 cooperates with guide bar 32 and lug 31 for supportingsection 12a of the respective rings 29. Since lthe end rings 9 areclamped to the heads 3 and 7,

these end rings are not provided with guide elements and each of theserings is cut away from its periphery and for a suitable distancecircumferentially to provide a notch 38 to accommodate the rod 37 whilepermitting of the necessary turning movement of rings 9.

Each of the guide bars 32 and 35 is provided with a series of boresextending from the inner side of the bar. These bores accommodatelocking balls 39 and expansion coil springs 40 confined between theballs and the inner ends of the bores. Each section of the respectiverings 29 is provided with a recess disposed for reception of theprojecting portionof the corresponding ball 39. The balls vare spacedalong the bars correspondingly to the desired spacing of the ring 29.Assuming that it is desired to space the rings 29 equidistantly fromeach other and from the rings 9, as shown, balls 39 are spacedaccordingly.

When the tubular blank 8 is properly positioned between the heads 3 and7, neck 6 opens into the blank through head 7. At its outer end, neck 6opens into a cylinder 45 rigidly secured upon the outer end of the neckin a suitable manner. A piston 46, disposed within cylinder 45 inoperative relation thereto, is secured upon the inner end of a pistonrod 47 of non-circular cross section, which is slidably mounted througha cover plate 48 secured upon the outer end of the cylinder. Piston rod47 comprises a screw shaft 49 which has threaded engagement with a nut50 mounted for rotation in bracket 4 and a plate 51 secured to the innerside of this bracket, the bracket and the plate cooperating to hold thenut against axial movement. A worm gear 52 extends circumferentially ofnut 50 and is conveniently formed vintegral therewith. This gear mesheswith a worm 53 secured upon a shaft 54 rotatably-mounted in bracket 4,this shaft 54 a suitable coupling 55, to shaft 56 of an electric motor57 appropriately mounted upon thel base of the machine or in any otherconvenient location. When motor 57 is in operation, cylinder 45 is movedaxially and lengthwise of the frame 1, this movement of the cylinderbeing guided by side bars 2a.

ofthe base frame.

With the various parts in the relative positions shownvin Figure 2,blank v8 and cylinder 45 are lled with a suitable fluid, preferably aliquid such as oil or'water. tirely satisfactory. Conveniently, a pipe60 `has Y one end screwed into a bore 61 opening through head 3 intoblank 8. This pipe communicates 1 with any suitable source of supply ofwater under Ordinarily, water is en-` .within the cylinder between theinner end thereof and piston 46, after which the valve 62 is closed. Anysuitable or preferred means may be provided for venting air from theblank and the cylinder, if desired. Venting means of this character arewell known and need not be illustrated nor described in detail. Also, ifdesired, pipe 60 may be provided, between valve 62 and head 3, with aloaded relief valve 63 of known type. Though this relief valve may notbe essential, as will be hereinafter more fully explained, I prefer toemploy a suitable relief valve as a precautionary measure.

As the corrugations are formed in the blank, which is extended outwardlybetween the die members'or rings, the effective diameter of the blank iscorrespondingly increased with theresult that the endwise pressureexerted by the blank, due to the internal pressure of the liquid, isalso increased so as to present increasing resistance to endwisecompression of the blank. For this reason the cylinder 45 is ofmaterially greater diameter than the corrugations to be formed, thediameter of the cylinder being suicient to assure that the pressureexerted thereon will overcome the endwise pressure exerted by the blankand the liquid therein when the pressure in the blankA and in thecylinder is of the same value per unit area. In the machine illustratedthe radius of the cylinder is inA excess of the diameter of thecorrugations to be produced which, under ordinary conditions, issuflicient. It will be understood, however, that the diameter of thecylinder relative to that of the blank may be varied considerably and asconditions require.

With the parts in position and the system `filled with water', as inFigure 2, the motor is set into operation so as to drivel the piston 46toward standard 5. This subjects the waterwithin cylinder 45 topressure, which pressure is transmitted to the inner end of the pistonand, through neck 6, to the water within blank 8. The piston and theblank are thus subjected to pressure from the same water column and thepressure per unit area within the blank is the same as the pressure perunit area exerted upon the inner end of cylinder 45. Blank 8 is thussubjected to internal radial pressure which tends to force the blankoutwardly between the die members and the blank is simultaneouslysubjected to endwise pressure by piston 45 acting through neck 6 andhead 7. Due to this arrangement, it follows that any radial and outwardmovement of the blank between the die-members will be accompanied by asimultaneous and corresponding endwise compression of the blank whicheffectively avoids stretching of the wall of the blank. In this manner,the metal of the blank is displaced and flowedv between the vdiemembers, avoiding stretching of the metal, the operation being one ofdisplacement and redistribution of the metal of the blank withoutvstretching thereof.

As the operation proceeds, the metal is flowed.

outwardly between the die .members and the blank is compressedor'contracted axially so as to move the die members together and shapethe corrugations as they are formed.

liu

During the first part of the operation the blank f eration the volume ofthe blank is materially increased, and this increase may be as much asper cent. This increase in volume is due to change in shape of the blankand not to any stretching of the metal wall thereof. As the blankincreases in volume, water is displaced from cylinder and flows into theblank to fill the same and maintain the pressure therein. Thisdisplacementof the water from the cylinder momentarily relieves thepressure exerted upon the inner end of the cylinder, thus avoidingsubjecting the blank toeffective endwise pressure momentarily at suchtime as the volume of the blank is increased with a resulting loweringof the internal pressure in the blank. In this manner, I provide anautomatic compensation for the increase in the volume of the blank andeliminate possibility of causing wrinkling thereof or distortion of thecorrugations being formed, such as would occur if the blank weresubjected to endwise pressure while the internal pressure therein wasmaterially lowered or non-existant. As the operation proceeds, thechange in the form of the blank causes reduction in the volume thereof,which is succeeded'by an increase in volume, and thereafter the volumeof the blank decreases. Since the unit area pressure is the same withinthe blank as it is within the cylinder, the water displaced from theblank, when the volume of the latter decreases, can flow therefrom intothe cylinder and will cause the latter to advance slightly relative tothe piston, While maintaining the pressure within the blank. In thismanner the cylinder and the piston cooperate to subject the blank toradial and axial pressure simultaneously while compensating forvariations in the volume of the blank during the corrugating operation,this compensating action effectively preventing the formation of bodywrinkles or the production of deformations in the corrugations produced.As a result, the corrugations in the completed bellows extend trulyradial thereof and the bellows is free of wrinkles or deformations whichwould impair its efficiency in use. During the successive stages of thecorrugating operation the tubular blank is reduced in length orcontracted axially and the displaced metal is flowed radially of theblank between the dies, which latter are moved toward each other so asto shape the corrugations as formed, the dies being in contact when thecorrugating operation has been completed, as in Figure 8. By removingthe pin 33 at one end of bar 35 and swinging this bar into inoperativeposition, sections 13a of die members 29 may be swung downwardly intoopen Kposition. After this has been done, the end die members 9 may beturned in a counterclockwise" direction so as to relieve the pressure onflanges 10 at the ends of the bellows, and sections 13 of the die rings9 are then swung downwardly into open position, after which the bellowsmay be removed from the dies. To permit of opening of sections 13 of dierings 9, each of the heads 3 and '7 is provided with suitably disposedslots 26a extending from the recesses 23 which receive the heads ofstuds 21 carried by section 13. Head '7 is then returned to its originalposition and the die members 29 are moved along bar 32 and rod 37 untilthey are engaged by the corresponding balls 39, after which a blank isinserted within the dies and secured to the heads 3 and 7 in the mannerpreviously described. Die members 29 are then locked closed, after bar35 has been secured in operative position, and the operationA above.described is repeated.

In the modified form illustrated in Figure 9, piston 46a is providedwith a tubular stem 65 which opens, at its inner end, into the spacebetween the inner end of the cylinder 45a and the piston. Stern isclosed at its outer end and is secured against endwise movement in asupport 66 rigid with members 2a of the frame. A suitable fluid,preferably a liquid such as water, is supplied to the bore 65a of stem65 under pressure from a pump 67, by means of a pipe 68 extending fromthe discharge of the pump, the intake of which is connected by a pipe 69to a suitable source of supply of water. The pump 67 is a gear pump ofknown type, though any other suitable or preferred means may be employedfor supplying liquid under pressure to the stem 65 of the piston. Theoperation of this form of the apparatus is similar to that of the formdisclosed in Figures 1 to 8, inclusive, with the exception that thepiston 46a is xed or stationary, and need not be described in detail.

In both forms of the apparatus the -resistance of the tubular blank toendwise pressure for contracting the same increases as the corrugationsare formed and increase in width radially of the blank.4 As a result, asthe corrugations decrease in width or thickness axially of the blank therate at which the blank is contracted axially is automatically reduced.This is advantageous as assuring that the metal in the corrugationsbeing formed will flow radially between the die rings and to the properextent before the rings are moved together. This eliminates danger ofcompressing the corrugations too rapidly axially as the metal is beingflowed between the die members and eliminates wrinkling or deformationof the corrugations from this cause.

While I have illustrated the apparatus of my invention as disposedhorizontally, I contemplate disposing such apparatus vertically ifdesired. The relief valve 63, while not essential, is preferablyprovided. This valve should be loaded to open in the event the pressurewithin the blank should, for anyreason, reach such a high value as tocause objectionable stretching of the metal of the blank. Otherwise, therelief valve is not brought into operation and, under normal conditions,may not be needed.

` What I claim isz- 1. In means for forming corrugated tubularelementsfrom tubular metal blanks, two heads disposed for receptiontherebetween of a tubular blank to ibezfcorrug'ated, one of the headshaving an opening therethrough into the blank and being movable'towardthe other head, spaced die members mounted between the heads forrelative movement toward each other and disposed to extend vabout theblank in operative relation thereto, and pressure applying means forsupplying fluid under pressure through said opening for subjecting theblank lto internal pressure while also subjecting said movable head topressure and forcing it toward the other head, said pressure applyingmeans comprising two members defining a space adapted for reception of afluid under pressure, said space communicating with said opening andsaidmembers having relative movement axially of the blank for compensatingfor variations in the volume of the blank during corrugating thereof.

2. In means for forming corrugated tubular elements from tubular metalblanks, two heads disposed for reception therebetween of a tubular blankto be corrugated, one of the heads having an opening therethrough intothe blank and being movable toward the other head, spaced die membersmounted between the heads for relative movement toward each other anddisposed to extend circumferentially of the blank in operative relationthereto, a cylinder rigid with the movable head and communicating at itsinner end with said opening, said cylinder being of materially greaterdiameter than the diameter of the corrugations to be produced, and apiston in the cylinder and cooperating therewith to subject the blank tointernal pressure and axial pressure simultaneously by uid conned underpressure between said piston and said inner end of the cylinder.

3. In means for forming corrugated tubular elements from tubular metalblanks, two heads disposed for reception therebetween of a tubular blankto be corrugated, one of the heads having an opening therethrough intothe blank and being movable toward the other head, spaced die membersmounted between the heads for relative movement toward each other anddisposed to extend circumferentially of the blank in operative relationthereto, a cylinder rigid with the movable head and communicating at itsinner end with said opening, said cylinder being of ma terially greaterdiameter than the diameter of the corrugations to be produced, a pistonoperating in the cylinder, and means for forcing the piston toward saidend of the cylinder, the piston and the cylinder cooperating to subjectthe blank to radial pressure and axial pressure simultaneously when theblank and the cylinder are filled with liquid and the piston is forcedtoward the inner end of the cylinder, said piston and cylinder beingcapable of relative movement to compensate for variations in the volumeof the Ablank during corrugating thereof.

4. In means for forming corrugated tubular elements from tubular metalblanks, a series o! spaced die members movable one toward the other, andmeans for supporting a tubular blank in operative relation to the diemembers with the latter extending circumferentially of the blank and forsubjecting the blank to simultaneous axial and radial pressure forextending it radially between the die members and contracting the blankaxially while forcing the die members toward each other to shape theresulting corrugations formed in the blank, said means comprising twomembers having, relative movement one toward and away from the other andelements defining a space adapted for reception of uid under pressureand communicating with the blank, said elements being capable ofrelative movement axially of the blank to compensate for variations inthe volume of the blank during corrugating thereof. v

5. In means for forming corrugated tubular elements from tubular metalblanks, two heads disposed for reception therebetween of a tubular blankto be corrugated, die members mounted between the heads in spacedrelation and for relative movement and disposed to extend about theblank circumferentially thereof, one of the heads having an openingtherethrough into the blank and being mounted for movement toward theother head, a cylinder rigid with the movable head and of materiallygreater diameter than the corrugations to be produced, said cylindercommunicating at its inner end with said opening, a xed piston withinthe cylinder, the cylinder having endwise movement relative to thepiston, and means for supplying liquid under pressure to the cylinderbetween the inner end thereof and said piston. f

HENRY H. BABCOCK.

